Based on the preceding discussion, the following inferences are drawn: (1) regardless of the cutoff option used the
Ea(L) and Ea(qo) functions are unimodal; however, when
inflow cutoff occurs during the advance phase, Ea could be
nearly insensitive to changes in qo, and as a result, the
maximum Ea may not be attained within physically realistic
ranges of qo; (2) there exist limiting conditions, which are
dependent on the field parameter set, that preclude the
applicability of the distance-based cutoff criterion in border
irrigation management; and (3) even when distance-based
inflow cutoff criterion is feasible, the corresponding design
and management scenario could be sub-optimal, in which
case, a near-optimal operation scenario can be realized only
with post-advance-phase cutoff